Hello,
I would like to know if Open MPI provides some kind of mechanism to select
collective algorithms such as MPI broadcast during run time depending on
some logic. For example, I would like to
use something like this:
if (some_condition) ompi_binomial_broadcast(...);
else ompi_pipeline_broa
Khalid,
i am not aware of such a mechanism.
/* there might be a way to use MPI_T_* mechanisms to force the algorithm,
and i will let other folks comment on that */
you definetly cannot directly invoke ompi_coll_tuned_bcast_intra_binomial
(abstraction violation, non portable, and you miss the som
Hello,
I'm trying to run the "connectivity_c" test on a variety of systems using
OpenMPI 1.8.4. The test returns segmentation faults when running across nodes
on one particular type of system, and only when using the openib BTL. (The test
runs without error if I stipulate "--mca btl tcp,self".)
Khalid,
The decision is rechecked every time we create a new communicator. So, you
might create a solution that force the algorithm to whatever you think it is
best (using the environment variables you mentioned), then create a
communicator, and free it once you’re done.
I have no idea what yo
George and Gilles, thank you for your answers.
@George, honestly I didn't know that the decision is rechecked for every
new communicator creation operation. I will try it. In fact we used
sub-communicators for some other research work previously and indeed it
outweigh the benefits for small mess
